code: def test_nlargest_boundary_float(
      self, nselect_method, float_numpy_dtype
  ):
      # GH#21426
      dtype_info = np.finfo(float_numpy_dtype)
      min_val, max_val = dtype_info.min, dtype_info.max
      min_2nd, max_2nd = np.nextafter(
          [min_val, max_val], 0, dtype=float_numpy_dtype
      )
      vals = [min_val, min_2nd, max_2nd, max_val]
      assert_check_nselect_boundary(
          vals, float_numpy_dtype, nselect_method
      )
  
file_path: pandas/pandas/tests/series/methods/test_nlargest.py
imports: import numpy
  import pytest
  import pandas
  from pandas import Series
  import pandas._testing
label_desc: Use image node_id 6 for calling the TestSeriesNLargestNSmallest obj's underlying member method code with example usage: obj.test_nlargest_boundary_float(nselect_method, float_numpy_dtype) without return types